CN116097047A

CN116097047A - Water heating device

Info

Publication number: CN116097047A
Application number: CN202180046961.4A
Authority: CN
Inventors: 尼尔斯·泰奥多尔·佩特利; 米夏·本雅明·迪赛尔库恩
Original assignee: Cook International Ltd
Current assignee: Cook International Ltd
Priority date: 2020-06-08
Filing date: 2021-06-08
Publication date: 2023-05-09
Also published as: IL298942A; CA3181887A1; KR20230038666A; JP2023539002A; EP4162211A1; NL2025785B1; WO2021251823A1; TW202210768A; US20230235919A1; AU2021290041A1

Abstract

The water heating device (10) comprises a water tank (12) provided with a tank wall (14). The water heating device (10) further comprises a vacuum container (20) enclosing a vacuum space (V). The tank (12) is entirely contained in the vacuum space, and the entire tank wall (14) is restricted by the vacuum. The vacuum vessel (20) is provided with a vacuum vessel wall (22) composed of a plurality of vacuum vessel wall portions that are hermetically connected to each other by fusion or welding. In addition, the water heating device (10) comprises at least one functional pipe (100, 200, 300, 400, 500) which extends through the tank wall (14) and is connected air-tightly to the tank wall (14) at the location of the tank wall connection (18). The functional tube (100, 200, 300, 400, 500) also extends through the vacuum vessel wall (22) and is connected gas-tightly with the vacuum vessel wall (22) at the location of the vacuum vessel wall connection (24).

Description

Water heating device

Technical Field

The present invention relates to a water heating apparatus for heating and maintaining hot water at a desired temperature, and which can be connected to a public water supply and to a kitchen faucet.

Background

EP 1173715 describes a water heating apparatus comprising a hot water tank and vacuum insulation. The configuration of the water heating device described in this patent is particularly suitable for storing pressurized water at temperatures above 100 ℃, so that instantaneously boiling water is dispensed when the water is dispensed, for example via a discharge valve. The hot water tank has an electrical heating element therein which heats the water and maintains it at a desired temperature. And, a temperature sensor is also provided, as well as a water supply pipe connectable to a public water supply system and a drain pipe connectable to a drain valve, for example. In EP 1173715, the upper side of the tank is provided with a flange, and the removable cover is bolted to this flange. On top of the removable cover, the hot water apparatus is provided with an insulating material to minimize heat loss through the cover. To further limit heat loss at the top and between the hot tank and the cold exterior jacket, the connection between the tank and the jacket is implemented as a thin-walled annular collar with which the tank is suspended connected to the jacket. Due to the heat resistance of this collar, the direct heat conduction losses between the hot box and the cold jacket are limited.

Disclosure of Invention

The present invention aims to provide a water heating apparatus which has a better efficiency than the known water heating apparatus. That is, with this water heating apparatus, less heat energy is lost when the hot water in the water tank of the water heating apparatus is maintained at the storage temperature.

To this end, the invention provides a water heating device according to claim 1. More particularly, the present invention provides a water heating apparatus comprising:

a tank comprising a tank wall;

a heating assembly contained in the water tank;

a vacuum vessel enclosing a vacuum space in which the water tank is entirely contained, the water tank wall being entirely limited by vacuum, the vacuum vessel including a vacuum vessel wall composed of a plurality of vacuum vessel wall parts, the vacuum vessel wall parts being hermetically connected to each other by welding or soldering; and

at least one functional tube extending through the tank wall and being connected air-tightly with the tank wall at the location of the tank wall connection, and the functional tube also extending through the vacuum vessel wall and being connected air-tightly with the vacuum vessel wall at the location of the vacuum vessel wall connection.

In the water heating device according to the invention, the tank is entirely surrounded by the vacuum jacket. This is in contrast to the water heating device described in the previous paragraph, which is provided with an insulating material on the cover of the tank and which is free of a vacuum jacket. With the configuration according to the invention, a better insulation is obtained, so that less heat loss occurs. Also, the heat conduction losses of the annular connection between the tank and the vacuum casing of the hot water apparatus described in the previous paragraph do not exist, since the tank is entirely surrounded by the vacuum space.

Furthermore, the water heating apparatus according to the invention has a more compact and simplified and lighter construction, thanks to the elimination of the required insulating material associated above the cover, the annular connection between tank and vacuum casing and the cover of the water heating apparatus as described in the previous paragraph.

Furthermore, thanks to the simplified construction of the water heating device according to the invention, it is almost entirely composed of metal parts, since it can be recovered properly and continuously and can be produced at low cost.

According to the use of so-called boiling water plantsThe water heating device of the invention has particular advantages. The volume is typically a total of 20 liters, more particularly preferably in the range of 3 liters to 8 liters. The maintenance temperature of the water in the tank is at least 90 ℃, and preferably in the range of 105 ℃ to 108 ℃. The pressure in the vacuum space is preferably 10 ^-4 mbar, preferably at least 10 ^-5 mbar。

Assuming a water tank volume of, for example, 3 liters and a maintenance temperature of 108 ℃, the hot water apparatus according to the invention is capable of achieving a heat loss of the hot water tank of approximately 2W, with 0.5W being the conduction loss and 1.5W being the radiation loss.

In one embodiment, the water tank may be carried separately by at least one functional tube.

Functional plumbing means that the plumbing must in any case have a function other than carrying a water tank. The functional pipe may be, for example, a water supply pipe or a water discharge pipe. Also, the tube may be a tube including a number of specific components therein, such as cables, electrical heating components, and/or temperature sensors. The pipe must extend into the tank interior and must also pass through the vacuum vessel wall. These tubes then form a heat conduction path from the water tank to the vacuum vessel wall. However, it is necessary that there are a plurality of such functional pipes and by providing these functional pipes with a further second function (i.e. carrying or supporting the water tank in the vacuum vessel) for which no additional heat transfer bridge is generated between the water tank wall and the vacuum vessel wall.

In an embodiment, the weight of the water tank can be transferred to the vacuum vessel wall via at least one functional tube. In this embodiment, the vacuum vessel wall may then further be used to support the entire hot water apparatus on a flat face/surface. In an alternative embodiment, the functional pipes can also be connected to an external fastening object, so that the weight of the hot water device is transferred directly to the external fastening object via the at least one functional pipe.

The portion of the at least one functional tube extending between the tank wall connection and the vacuum vessel wall connection determines the heat transfer length of the heat transfer from the tank wall connection to the vacuum vessel wall connectionl _h And the portion has a wall cross-sectional area a. When rib-like or telescopic-like functional pipe members are used, the heat transfer length l _h May be greater than the length of the tube. In one embodiment, the heat transfer length in mm/ _h In mm ² The ratio between wall cross-sectional areas a in units satisfies the following formula: l (L) _h /A>4mm ^-1 . Assuming that the quotient of the heat transfer length divided by the wall cross-sectional area is within this range, the heat conduction through the at least one functional pipe may be limited such that the heat loss through the heat conduction through the at least one functional pipe is almost negligible.

The portion extending between the tank wall connection and the vacuum vessel wall connection with the at least one functional pipe has a heat transfer length l of more than 60mm _h Similar slight heat losses can also be achieved for the embodiments of (a). Furthermore, the material of the at least one functional tube is preferably stainless steel or a similar metal with a relatively low thermal conductivity. Naturally, when the wall thickness of the stainless steel functional tube is in the range of 0.4 to 1.0mm and the diameter is less than 8mm, the heat conduction from the water tank to the vacuum vessel wall via the at least one functional tube can be neglected.

The water tank may include a cylindrical water tank sidewall and the vacuum vessel may include a cylindrical vacuum vessel sidewall. To further increase the efficiency of the water heating apparatus, in one embodiment, a laminate of a reflective foil and a glass fiber cloth may be included at least between the cylindrical tank side wall and the cylindrical vacuum vessel side wall.

Drawings

Further description of the invention is described in the accompanying claims and will be further described below with reference to one or more examples in the drawings.

Fig. 1 schematically shows a cross-sectional view of a first embodiment of a water heating device;

fig. 2 schematically shows a cross-sectional view of a second embodiment of a water heating device;

fig. 3 schematically shows a cross-sectional view of a third embodiment of a water heating device;

FIG. 4 shows an example of the embodiment presented in outline in FIG. 3; and

fig. 5 shows a perspective cross-sectional view of the example of fig. 4.

Detailed Description

In the following detailed description, corresponding parts of the different embodiments are indicated with the same reference numerals. This detailed description is not merely an example of the kind presented in the accompanying drawings. The reference signs indicated in the detailed description and claims are not limiting and are only used to clarify the various embodiments described in the detailed description by referring to the several examples presented in the drawings.

In its broadest aspect, the present invention relates to a water heating apparatus 10 comprising a water tank 12 provided with a tank wall 14. Contained within the water tank 12 is a heating assembly 28. The water heating apparatus 10 further includes a vacuum vessel 20 enclosing a vacuum space V. The water tank 12 is entirely contained in the vacuum space V, and the entire tank wall 14 is restricted by the vacuum. The vacuum vessel 20 is provided with a vacuum vessel wall 22 composed of a plurality of vacuum vessel portions hermetically connected to each other by fusion or welding. Furthermore, the water heating device 10 comprises at least one

functional pipe

100, 200, 300, 400, 500 which extends through the tank wall 14 and is connected air-tightly with the tank wall 14 at the location of the tank wall connection 18. This

functional tube

100, 200, 300, 400, 500 also extends through the vacuum vessel wall 22 and is connected air-tightly with the vacuum vessel wall 22 at the location of the vacuum vessel wall connection 24.

The advantages of this water heating apparatus, as indicated above in its broadest aspects, have been described in the summary of the invention, and the advantages described herein are understood to be incorporated by reference herein.

In the example of the embodiment presented generally in fig. 1, the tank 12 may be supported by a plurality of supports 16. Preferably, these supports 16 are realized in a material that conducts heat poorly and also releases as little gas as possible, so that the vacuum in the vacuum blank V is not disturbed. Also, it is preferable that the contact area between the support 16 and the water tank 12 is as small as possible to limit the heat conduction through the support 16 to a minimum.

As already described in the above summary paragraphs, in one embodiment (examples are shown in fig. 2-4), the water tank 12 may be individually carried by at least one

functional tube

100, 200, 300, 400, and/or 500. Furthermore, in further illustration of this embodiment, the weight of the water tank 12 may be transferred to the vacuum vessel wall 22 via at least one

functional tube

100, 200, 300, 400, and/or 500.

The portion of the at least one

functional tube

100, 200, 300, 400 and/or 500 extending between the tank wall connection 18 and the vacuum wall connection 24 has a heat transfer length l _h And a wall cross-sectional area a. In one embodiment, the heat transfer length in mm/ _h In mm ² The ratio between wall cross-sectional areas a in units may satisfy the following equation: l (L) _h /A>4mm ^-1 。

In an embodiment, the portion of the at least one

functional tube

100, 200, 300, 400 and/or 500 extending between the tank wall connection 18 and the vacuum vessel wall connection 24 may have a heat transfer length l of greater than 60mm _h . Furthermore, the material of the at least one functional tube is preferably one of stainless steel, titanium alloy or nickel-iron-chromium alloy (Incoloy).

In an exemplary embodiment, examples of which are shown in fig. 1-5, at least one

functional tube

100, 200, 300, 400, and/or 500 may have an outer diameter of less than 8 mm.

Furthermore, it is preferred that at least one

functional tube

100, 200, 300, 400 and/or 500 has a wall thickness of between 0.4 and 1.0 mm.

In one embodiment, the previously mentioned tank wall connection 18 between the at least one functional tube and the tank wall and the vacuum vessel wall connection 24 between the at least one functional tube and the vacuum vessel wall may be fusion joints.

In an alternative embodiment, the previously mentioned tank wall connection 18 between the at least one functional pipe and the tank wall and the vacuum vessel wall connection 24 between the at least one functional pipe and the vacuum vessel wall may be welded joints.

In an embodiment, an example is shown in fig. 1-5, the at least one

functional pipe

100, 200, 300, 400, and/or 500 may include at least one of the following: a water supply pipe 100, a water discharge pipe 200,

pipe members

300, 400 including an electric heating assembly, and pipe member 500 including a temperature sensor.

In an embodiment, an example is shown in fig. 1-5, the water tank 12 may include a cylindrical water tank sidewall, and the vacuum vessel 20 may have a cylindrical vacuum vessel sidewall. Furthermore, to reduce radiation losses, a laminate of a reflective foil and a glass fiber cloth may be included at least between the cylindrical tank side wall and the cylindrical vacuum vessel side wall.

A substantial reduction in radiation loss is obtained, for example, when the laminate comprises at least three layers of reflective foil and at least three layers of glass fibre cloth.

In an embodiment, an example is shown in fig. 3, 4 and 5, at least one

functional pipe

100, 200, 300, 400, 500 may be provided with: the

first pipe section

102, 202, 302, 402, 502; a

first bend

104, 204, 304, 404, 504 connecting the

first conduit portion

102, 202, 302, 402, 502 with the

second conduit portion

106, 206, 306, 406, 506; a

second bend

108, 208, 308, 408, 508 connecting the

second conduit portion

106, 206, 306, 406, 506 with the

third conduit portion

110, 210, 310, 410, 510. The

first pipe portion

102, 202, 302, 402, 502 then extends through the upper side of the vacuum vessel 20. The

third pipe portion

110, 210, 310, 410, 510 extends through the underside of the tank 12. Also, the

first pipe portion

102, 202, 302, 402, 502 extends substantially vertically between the tank wall 14 and the vacuum vessel wall 22.

This embodiment has the advantage that the first pipe sections are particularly long so that the heat transferred via those first pipe sections to the vacuum vessel wall 22 is largely limited.

In an embodiment, examples are shown in fig. 3, 4 and 5, the at least one functional tube comprises:

a first functional pipe 100, which is a water supply pipe, extends through and is hermetically connected to the first vacuum top wall opening, and extends through and is hermetically connected to the first tank bottom wall opening;

a second functional tube 200, which is a drain tube, extends through and is air-tightly connected to the second vacuum top wall opening, and extends through and is air-tightly connected to the second tank bottom wall opening;

a third functional tube 300, which is a first heating assembly tube, extending through and being air-tightly connected to the third vacuum top wall opening, and extending through and being air-tightly connected to the third tank bottom wall opening; and

a fourth functional tube 400, which is a second heating element tube, extends through and is air-tightly connected to the fourth vacuum top wall opening and extends through and is air-tightly connected to the fourth tank bottom wall opening, wherein the third tube 300 and the fourth tube 400 are connected to each other via the coil portion 28, and the third tube 300, the fourth tube 400 and the coil portion 28 form an integral one-piece part comprising the heating element and the cables connected to the heating element.

Finally, the at least one functional tube may further comprise a fifth functional tube 500 being a sensor tube extending through and being air-tightly connected to the fifth vacuum top wall opening and extending through and being air-tightly connected to the fifth water tank bottom wall opening. In the sensor tube, at least one temperature sensor and a cable connected to the temperature sensor may be included.

In one embodiment, the water tank and the vacuum vessel may each have a cylindrical configuration. Further, the respective centers of the top wall openings of the first, second, third, fourth and fifth vacuum vessels are located on a common pitch circle having a diameter greater than the outer diameter of the cylindrical water tank and less than the inner diameter of the cylindrical vacuum vessel, and the center of the common pitch circle is located on the vertical axis of the cylindrical vacuum vessel.

According to an embodiment, the respective centers of the first, second, third, fourth and fifth tank bottom wall openings (if any) may lie in a common vertical plane.

In an embodiment shown in fig. 5, a spacer 30, such as, for example, a ceramic ring, made of a material having a thermal conductivity of less than 5W/(m.k), may be included between the

first pipe portion

102, 202, 302, 402, 502 of the at least one

functional pipe

100, 200, 300, 400, 500 and the vacuum vessel wall 22. Preferably, this spacer 30 may be arranged adjacent to the transition between the tank bottom side and the tank side wall.

In one embodiment illustrated in fig. 4 and 5, at least one

first pipe portion

102, 202, 302, 402, 502 may solely abut the tank wall 12 at a transition between the tank bottom side and the tank side wall.

In one embodiment shown in fig. 4 and 5, the transition of the upper side of the tank and the side wall of the tank and the upper portion of at least the

first pipe portion

102, 202, 302, 402, 502 may be at a distance from each other.

In one embodiment shown in fig. 4 and 5, the upper portion of at least the

first pipe portion

102, 202, 302, 402, 502 and the upper side of the tank may be fixed relative to each other by means of a fixing assembly.

This securing component may be a second spacer 32, an example of which is shown in fig. 4 and 5. The second spacer 32 may keep the tank 12 and the upper portion of the

first pipe portion

102, 202, 302, 402, 502 of the at least one

functional tube

100, 200, 300, 400, 500 at a distance from each other adjacent to the transition of the upper side of the tank and the tank side wall. The second spacer 32 engages the water tank and engages the upper portion of the

first pipe portion

102, 202, 302, 402, 502 of the at least one

functional pipe

100, 200, 300, 400, 500.

In further illustration of this embodiment, engagement of the second spacer 32 with the tank may be achieved on top of the tank 12 at the axial location of the tank 12. The engagement of the second spacer 32 with the upper portion of the

first pipe portion

102, 202, 302, 402, 502 of the at least one

functional pipe

100, 200, 300, 400, 500 may be achieved on one or both

upper portions

102, 402.

The second spacer 32 is in the example shown embodied as a thin-walled component having a small cross-sectional area in order to make the heat conduction from the water tank 12 to the

first pipe portion

102, 402 through the second spacer 32 as small as possible. The second spacer 32 may absorb both pressure and tension, which relates to the stability of the tank 12 in the vacuum vessel 20 (especially during transportation of the hot water apparatus) to avoid damage.

The invention is not limited to the embodiments described, nor to the examples shown in the drawings. The drawings and reference numerals are used for illustration purposes only and are not limiting. The invention is defined by the appended claims.

Claims

1. A water heating apparatus comprising:

-a tank (12) comprising a tank wall (14);

-a heating assembly (28) contained in the water tank (12);

-a vacuum vessel (20) enclosing a vacuum space (V), the water tank (12) being entirely contained in the vacuum space (V), the water tank wall (14) being entirely vacuum-limited, the vacuum vessel (20) comprising a vacuum vessel wall (22) consisting of a plurality of vacuum vessel wall parts, the vacuum vessel wall parts being air-tightly connected to each other by welding or soldering; and

-at least one functional tube (100, 200, 300, 400 and/or 500) extending through the tank wall (14) and being air-tightly connected with the tank wall (14) at the location of the tank wall connection (18), and the functional tube (100, 200, 300, 400 and/or 500) also extending through the vacuum vessel wall (22) and being air-tightly connected with the vacuum vessel wall (22) at the location of the vacuum vessel wall connection (24).

2. The water heating device according to claim 1, wherein the tank (12) is carried solely by the at least one functional pipe (100, 200, 300, 400 and/or 500).

3. The water heating apparatus according to claim 2, wherein the weight of the water tank (12) is transferred to the vacuum vessel wall (22) via the at least one functional tube (100, 200, 300, 400 and/or 500).

4. The water heating device according to any one of the preceding claims, wherein the at least one functional pipe (100, 200, 300, 400 and/or 500) is in the water tankThe portion extending between the wall connection (18) and the vacuum vessel wall connection (24) determines the heat transfer length l of the heat transfer from the tank wall connection (18) to the vacuum vessel wall connection (24) _h And the portion has a wall cross-sectional area A in which the heat transfer length l in mm _h In mm ² The ratio between wall cross-sectional areas a in units satisfies the following equation: l (L) _h /A>4mm ^-1 。

5. The water heating apparatus according to any one of the preceding claims, wherein the portion of the at least one functional tube (100, 200, 300, 400 and/or 500) extending between the tank wall connection (18) and the vacuum vessel wall connection (24) has a heat transfer length l of more than 60mm _h Wherein the material of the at least one functional tube is one of stainless steel, titanium alloy or nickel-iron-chromium alloy.

6. The water heating device according to any one of the preceding claims, wherein the at least one functional pipe (100, 200, 300, 400 and/or 500) has an outer diameter of less than 8 mm.

7. The water heating device according to any one of the preceding claims, wherein the at least one functional tube (100, 200, 300, 400 and/or 500) has a wall thickness of between 0.4 and 1.0 mm.

8. The water heating apparatus according to any one of the preceding claims, wherein the tank wall connection (18) and the vacuum vessel wall connection (24) are welded joints.

9. The water heating apparatus according to any one of the preceding claims, wherein the tank wall connection (18) and the vacuum vessel wall connection (24) are welded joints.

10. The water heating apparatus according to any one of the preceding claims, wherein the at least one functional pipe (100, 200, 300, 400 and/or 500) comprises at least one of a water supply pipe (100), a water discharge pipe (200), a pipe (300, 400) containing an electrical heating assembly and a pipe (500) containing a temperature sensor.

11. The water heating apparatus according to any one of the preceding claims, wherein the tank (12) comprises a cylindrical tank sidewall, and wherein the vacuum vessel (20) comprises a cylindrical vacuum vessel sidewall, comprising a laminate of a reflective foil and a glass fiber cloth at least between the cylindrical tank sidewall and the cylindrical vacuum vessel sidewall.

12. The water heating apparatus according to claim 11, wherein the laminate comprises at least three layers of reflective foil and at least three layers of fiberglass cloth.

13. The water heating apparatus according to any one of the preceding claims, wherein the at least one functional pipe (100, 200, 300, 400, 500) comprises a first pipe section (102, 202, 302, 402, 502), a first bend (104, 204, 304, 404, 504) connecting the first pipe section (102, 202, 302, 402, 502) with a second pipe section (106, 206, 306, 406, 506), and a second bend (108, 208, 308, 408, 508) connecting the second pipe section (106, 206, 306, 406, 506) with a third pipe section (110, 210, 310, 410, 510);

wherein the first pipe portion (102, 202, 302, 402, 502) extends through an upper side of the vacuum vessel (20);

wherein the third pipe portion (110, 210, 310, 410, 510) extends through the bottom side of the tank (12);

wherein the first pipe portion (102, 202, 302, 402, 502) extends substantially vertically between the tank wall (14) and the vacuum vessel wall (22).

14. The water heating apparatus according to claim 13, wherein the at least one functional tube comprises:

-a first functional pipe (100) being a water supply pipe, the first functional pipe extending through and being air-tightly connected with the first vacuum top wall opening and extending through and being air-tightly connected with the first tank bottom wall opening;

-a second functional tube (200) being a drain tube extending through and being air-tightly connected with the second vacuum top wall opening and extending through and being air-tightly connected with the second tank bottom wall opening;

-a third functional tube (300) being a first heating assembly tube portion, the third functional tube extending through and being air-tightly connected with a third vacuum top wall opening and extending through and being air-tightly connected with a third water tank bottom wall opening;

-a fourth functional tube (400) being a second heating assembly tube part, the fourth functional tube extending through and being air-tightly connected with a fourth vacuum top wall opening and extending through and being air-tightly connected with a fourth water tank bottom wall opening, wherein the third functional tube (300) and the fourth functional tube (400) are connected to each other via a coil part (28), wherein the third functional tube (300), the fourth functional tube (400) and the coil part (28) form an integral one-piece part, the integral one-piece part comprising a heating assembly and a cable connected to the heating assembly; and

-a fifth functional tube (500) being a sensor tube extending through and being air-tightly connected with a fifth vacuum top wall opening and extending through and being air-tightly connected with a fifth water tank bottom wall opening, wherein at least one temperature sensor and a cable connected to the temperature sensor are comprised in the sensor tube.

15. The water heating apparatus according to claim 14, wherein the water tank (12) and the vacuum vessel (20) each have a cylindrical configuration, wherein the respective centers of the first vacuum vessel top wall opening, the second vacuum vessel top wall opening, the third vacuum vessel top wall opening, the fourth vacuum vessel top wall opening and the fifth vacuum vessel top wall opening are located on a common pitch circle, the common pitch circle having a diameter that is larger than the outer diameter of the cylindrical water tank (12) and smaller than the inner diameter of the cylindrical vacuum vessel (20), and the center of the common pitch circle is located on the vertical axis of the cylindrical vacuum vessel (20).

16. The water heating apparatus according to claim 14 or 15, wherein the respective centers of the first tank bottom wall opening, the second tank bottom wall opening, the third tank bottom wall opening, the fourth tank bottom wall opening and the fifth tank bottom wall opening lie in a common vertical plane.

17. The water heating apparatus according to any one of claims 13 to 16, wherein a first spacer (30) is comprised between the first pipe portion (102, 202, 302, 402, 502) of the at least one functional pipe (100, 200, 300, 400, 500) and the vacuum vessel wall (22), the first spacer being made of a material having a thermal conductivity of less than 5W/(m.k), such as for example a ceramic ring.

18. The water heating apparatus according to any one of claims 13 to 17, wherein the at least first pipe portion (102, 202, 302, 402, 502) solely abuts against the tank wall at a transition between the tank bottom side and the tank side wall (14).

19. The water heating apparatus according to claim 17 or 18, wherein a transition between the upper side of the tank and the side wall of the tank and an upper portion of the at least first pipe portion (102, 202, 302, 402, 502) are at a distance from each other.

20. The water heating apparatus according to claim 19, wherein at least an upper portion of the first pipe portion (102, 202, 302, 402, 502) and an upper side of the tank are fixed relative to each other with a fixing assembly.

21. The water heating apparatus according to claim 20, wherein the fixing assembly is embodied as a second spacer (32) which keeps the water tank (12) and an upper portion of the first pipe portion (102, 202, 302, 402, 502) of the at least one functional pipe (100, 200, 300, 400, 500) at a distance from each other adjacent to a transition between an upper side of the water tank and a side wall of the water tank, and which engages the water tank (12) and engages an upper portion of the first pipe portion (102, 202, 302, 402, 502) of the at least one functional pipe (100, 200, 300, 400, 500).

22. The water heating device according to claim 21, wherein the engagement of the second spacer (32) with the water tank (12) is effected on an upper side of the water tank (12) at a position of an axis of the water tank, and wherein the engagement of the spacer with an upper portion of the first pipe portion (102, 202, 302, 402, 502) of the at least one functional tube (100, 200, 300, 400, 500) is effected on one upper portion or on both upper portions (102, 402).